Workshop #3:
Creating an Exceptional Science Fair Project
Experimental
Design
07 October 2014
SCSD Science Fair Workshop Mentoring Program 2014/2015
1
Project Organization
Hypothesis
Purpose
Experimental
design, methods
and materials
Data Analysis Discussion
Background InformaGon
Results and Data
Conclusions
References
07 October 2014
SCSD Science Fair Workshop Mentoring Program 2014/2015
2
Stating the Obvious..?
• What exactly are you trying to
measure?
• Will the experiment you’re planning
generate data to test your hypothesis?
07 October 2014
SCSD Science Fair Workshop Mentoring Program 2014/2015
3
“Scouting” Experiments
• Quick “scouting” experiments show
the feasibility of the concept and
experimental method.
• Define the “dynamic range”
• Learn from your mistakes!
Example: Your hypothesis is that reducing the air pressure in
a soccer ball will result in shorter kicks. Before building an
automated soccer ball kicking machine to measure the
effect, try a few kicks with under inflated balls to be sure the
trend is as you hypothesized.
07 October 2014
SCSD Science Fair Workshop Mentoring Program 2014/2015
4
Scientific Credibility
• …or, why should I believe you?
• Only change one variable in each set of
experiments (temperature, time,
concentration…)
• When possible run a control experiment
– Is the variable you’re changing really
responsible for the result?
• Control or record as many environmental
conditions as possible
– You are keeping a lab book, aren’t you?
07 October 2014
SCSD Science Fair Workshop Mentoring Program 2014/2015
5
Accuracy and Precision
• Accuracy can be hard to achieve
– Needs well calibrated reference measurements
07 October 2014
SCSD Science Fair Workshop Mentoring Program 2014/2015
6
Uncertainty and Repeats
• Determine the precision of your measurements by
repeating your experiments “n-times”
• Estimate Standard Deviation for data
– Use for Error Bars on graphs
07 October 2014
SCSD Science Fair Workshop Mentoring Program 2014/2015
7
Experimental bias: “Blind” testing
Plain old vanilla
New and Improved
Greenhouse Gasser
• Try to avoid introducing bias into the experiments
- let the DATA speak for itself!
07 October 2014
SCSD Science Fair Workshop Mentoring Program 2014/2015
8
Experimental Design:
Running a Control
• A control experiment is
used to validate that your
experimental method
produces results that agree
with generally known
results.
Example: Your hypothesis is
that growing radishes
aeroponically hanging in air
will elongate them.
Hanging
Control
As a control you need to grow
some in soil to be sure the bag
of seeds you have produces
round radishes.
07 October 2014
SCSD Science Fair Workshop Mentoring Program 2014/2015
9
Experimental Design: Review
If possible do some scouGng experiments to
validate you are on the right track.
Design a set of experiments where only one variable is changed at a Gme.
1
Control environmental condiGons.
Do a sufficient number of replicates to
demonstrate the variability in your
measurements does not invalidate your results!
Run a reference or control when possible
07 October 2014
SCSD Science Fair Workshop Mentoring Program 2014/2015
10
Methods Section
• Write a brief description of the experimental
methods
• Describe any apparatus that is going to be built,
use drawings and pictures
• Explain the variable tested in each experiment
• Explain the parameters held constant
• Explain how many replicates will be run and why
• Describe the control experiments you will use
07 October 2014
SCSD Science Fair Workshop Mentoring Program 2014/2015
11
Materials Section
• Make a list of the equipment and materials
•
•
•
•
•
•
•
•
•
Mettler AE 50 scale
Barnant co. 400-2901 vacuum-pressure pump
Clear green helium balloons (17)
Texas Instruments Ti-89 titanium edition graphing calculator
Microsoft Office 2000 small business edition
Dell dimension 8100 computer
Blue pen (Bic Biro)
Sharpies (silver, blue, green, black)
Helium (Industrial grade)
• Allows other scientists to replicate your work
07 October 2014
SCSD Science Fair Workshop Mentoring Program 2014/2015
12
Getting Started with
Your Experiments
•
Use a notebook to record observations
and data
•
Take pictures as you work, they will make
your project more interesting and help fill
in the board
•
Be flexible, learn from your discoveries
and modify your project as necessary
•
Enter your data into spreadsheets and
plot out the results frequently to be sure
everything makes sense
07 October 2014
SCSD Science Fair Workshop Mentoring Program 2014/2015
13
07 October 2014
SCSD Science Fair Workshop Mentoring Program 2014/2015
Demonstration…
Snoopy’s Hypothesis:
The speed of the plane will increase linearly
with motor power: double the power, double
the speed!
07 October 2014
SCSD Science Fair Workshop Mentoring Program 2014/2015
15